• Composites Research
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• 제12권5호
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• pp.23-30
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• 1999

Fiber reinforced composite materials are widely used in automotive industry to produce parts that are large, thin, lightweight, strong and stiff. It is very important to know a charge shape in order to have good products in the compression molding. In particular, the product such as a bumper beam is composed of the random and unidirectional fiber mats. The characteristics of flow fronts such as a bulging phenomenon for random mat and unidirectional fiber mat and slip parameters are studied numerically. And the effects of viscosity ratio and stack type on mold filling parameters are also discussed.

• Journal of the Korean Data and Information Science Society
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• 제15권2호
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• pp.405-411
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• 2004

In the analysis of cancer data, it is important to make inferences of survival function and to assess the effects of covariates. Cox's proportional hazard model(PHM) and Beran's nonparametric method are generally used to estimate the survival function with covariates. We adjusted the incomplete survival time using the Buckley and James's(1979) pseudo random variables, and then proposed the estimator for the conditional survival function. Also, we carried out the simulation studies to compare the performances of the proposed method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 전기설비
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• pp.12-15
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• 2005

The subject of this research is not only to examine effects on electrical wiring that voltage drops make in low voltage load facilities found in apartments, buildings street lightings, factories, and etc, but also to discuss the voltage drops computation program on distributed random loads to optimize their safety and economy.

• 한국산학기술학회논문지
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• 제13권2호
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• pp.755-759
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• 2012

본 논문에서는 의학, 게임분야에서 활용되는 하드웨어 기반의 난수 발생기에 관한 것이다. 인텔은 하드웨어 기반 실난수 발생기의 보안성에 대한 가이드라인을 제시한 바 있다. 주로 존슨 열 잡음원을 사용하며, 듀얼 오실레이터나 폰 노이만 수집기를 적용하고 있다. 하드웨어 기반의 난수 발생기는 NIST 통계검정, FIPS140-1을 포함한 다양한 테스트 유형을 적용하고 있다. 본 논문에서는 하드웨어 잡음원의 출력열에 필터링 기법 영향으로부터 난수성 변화 정도를 측정하였다.

• Journal of Mechanical Science and Technology
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• 제17권7호
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• pp.966-977
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• 2003

This paper investigates how intentional mistuning of bladed disks reduces their sensitivity to unintentional random mistuning. The class of intentionally mistuned disks considered here is limited, for cost reasons, to arrangements of two types of blades (A and B, say). A two-step procedure is then described to optimize the arrangement of these blades around the disk to reduce the effects of unintentional random mistuning. First, a pure optimization effort is undertaken to obtain the pattern (s) of the A and B blades that yields small/the smallest value of the largest amplitude of response to a given excitation in the absence of unintentional random mistuning using Genetic Algorithm. Then, in the second step, a qualitative/quantitative estimate of the sensitivity for the optimized intentionally mistuned bladed disks with respect to unintentional random mistuning is performed by analyzing their amplification factor, probability density function and passband/stopband structures. Examples of application with simple bladed disk models demonstrate the significant benefits of using this class of intentionally mistuned disks.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 1999년도 추계학술발표대회 논문집
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• pp.101-106
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• 1999

Fiber reinforced plastic composites is widely used to make be lightening of aircraft and automotive owing to having high specific strength and specific modulus. And it is very important to know a charge shape in order to have good products in the compression molding. In particular, the product such as a bumper beam is composed of the random and unidirectional composite mats. Its deformation and charge shape are very different by stack type of random and unidirectional mats. In this paper, the characteristics of flow fronts such as a bulging phenomenon for step-type random/unidirectional composite mats and slip parameters are studied numerically. And the effects of viscosity ratio and stack type on the mold filling parameters are also discussed.

• Journal of Mechanical Science and Technology
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• 제16권5호
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• pp.583-590
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• 2002

When a mechanical structure is driven by stationary wide band random point forces, the resulting vibration depends upon the number, location, and joint statistical properties of the exciting forces. In this study, under the assumption of light damping, an approximate procedure for analyzing plates is briefly outlined. The effects of number, location and correlation of the force field on the vibration level are then investigated for various cases in which random point forces with band limited white noise are applied, and the optimal spacing between input forces that produces a relative minimum in the vibration response is predicted.

• Communications for Statistical Applications and Methods
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• 제22권6호
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• pp.625-637
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• 2015

We develop a Bayesian clustering procedure based on a Dirichlet process prior with cluster specific random effects. Gibbs sampling of a normal mixture of linear mixed regressions with a Dirichlet process was implemented to calculate posterior probabilities when the number of clusters was unknown. Our approach (unlike its counterparts) provides simultaneous partitioning and parameter estimation with the computation of the classification probabilities. A Monte Carlo study of curve estimation results showed that the model was useful for function estimation. We find that the proposed Dirichlet process mixture model with cluster specific random effects detects clusters sensitively by combining vague edges into different clusters. Examples are given to show how these models perform on real data.

• Communications for Statistical Applications and Methods
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• 제16권6호
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• pp.971-978
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• 2009

Poisson generalized linear mixed models(GLMMs) have been widely used for the analysis of clustered or correlated count data. For the inference marginal likelihood, which is obtained by integrating out random effects is often used. It gives maximum likelihood(ML) estimator, but the integration is usually intractable. In this paper, we propose how to obtain the ML estimator via Laplace approximation based on hierarchical-likelihood (h-likelihood) approach under the Poisson GLMMs. In particular, the h-likelihood avoids the integration itself and gives a statistically efficient procedure for various random-effect models including GLMMs. The proposed method is illustrated using two practical examples and simulation studies.

• JSTS:Journal of Semiconductor Technology and Science
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• 제14권4호
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• pp.365-375
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• 2014

This paper proposes an abnormal V-shaped-error-free non-blind deconvolution technique featuring an adaptively segmented forward-problem based iterative deconvolution (ASDCN) process. Unlike the algebraic based inverse operations, this eliminates any operations of differential and division by zero to successfully circumvent the issue on the abnormal V-shaped error. This effectiveness has been demonstrated for the first time with applying to a real analysis for the effects of the Random Telegraph Noise (RTN) and/or Random Dopant Fluctuation (RDF) on the overall SRAM margin variations. It has been shown that the proposed ASDCN technique can reduce its relative errors of RTN deconvolution by $10^{13}$ to $10^{15}$ fold, which are good enough for avoiding the abnormal ringing errors in the RTN deconvolution process. This enables to suppress the cdf error of the convolution of the RTN with the RDF (i.e., fail-bit-count error) to $1/10^{10}$ error for the conventional algorithm.